David O'Connor, “Dr. Tomato,” and Loretta Salazar at their castle in Barrington. (Courtesy photo)

You may know him as Dr. Tomato, or Lord Duncan.

You might have come to him for personal training, to look at fossils, or to get information on making your vegetables grow.

He's been a professional athlete, a private eye, a gemologist, an inventor and a performer, to name a few. And his home is indeed his castle.

Detailing all of David O'Connor's adventures in one article would be near impossible. But for the Barrington resident, living life to the fullest is just how things should be done.

“On my last day, my biggest fear is that I had 10,000 things to do, and I only did two,” he said. “I want to be the opposite of that — to say 'there were two things I didn't get to, but I tried the other 9,998.'”

It is clear that O'Connor has followed his life's passions, wherever they have taken him. Most obvious among them is his home, Castle Anam Cara. O'Connor, along with his longtime partner, Loretta Salazar, engineered, designed and built the castle using 10th Century techniques.

While they worked on the castle, they lived in a tent for two years, enduring two long New Hampshire winters.

“The thing that kept us going was thinking about gathering around an antique stove in the evening, eating fresh-baked bread,” O'Connor said. “There was a lot of commitment between day one and that first fire. Sometimes we would look at each other and say, 'This was your idea.' ”

The idea, in fact, was born more from practicality than from a particular vision that O'Connor or Salazar had.

“Our philosophy was to have a place where we're responsible for everything,” O'Connor said. “We wanted something simple, that would bring us to a quieter time and place.”

The couple considered building a samurai dwelling, or a Viking longhouse. However, they realized that their Barrington property lent itself well to a castle, which would allow them to keep the footprint small (less clearing of land), and to use the rock that they excavated.

The construction took four and a half years, and Castle Anam Cara has been completed for 18 years, although the work is never fully finished.

The two-story castle is filled with antiques and relics, ranging from ancient scripts to dinosaur dung. Walking around, visitors feel as if they've been transported to the Middle Ages — the rooms are cool and dark, with tapestries and paintings for decoration. Castle Anam Cara is open to school groups, and when the kids visit there is nothing visible that wouldn't be found in tenth-century Europe.

However, for their personal life, O'Connor and Salazar make a few concessions to modernity. There is electricity, a wood-burning stove and running water.

“Our desire wasn't to make life miserable,” O'Connor said. “If you asked anyone in the 10th Century if they would want a bathroom or to be able to heat with wood they would have said yes. We do live in the 21st Century, and at night I like a hot shower.”

Even with the modern conveniences, Castle Anam Cara's environmental impact is tiny. There are solar panels on the roof and all heating and cooking is done with wood.

“It is designed to be efficient and simple,” O'Connor said. “It's built to work well and have a low carbon footprint. We try to be extremely responsible.”

The environment, after all, is another of O'Connor's passions. Castle Anam Cara is surrounded by lush gardens and greenhouses, where the lord and lady grow all of their own food.

When it comes to growing, O'Connor is not looking to the past, but rather is at the forefront of the latest science. He is interested in using data and good business practices to innovate ways to solve the problem of growing enough food to feed the world's rapidly expanding population.

“I trained as a scientist, and I try to apply science to everything I do,” said O'Connor, who graduated from Dartmouth. “The whole issue could benefit from all sides seeing the science. It comes down to the consumer. The individual has the ability to research themselves, and to make decisions based on science, not advertisements.”

Like any good scientist, O'Connor believes that the answer to the world's agricultural problems lies in the middle rather than the extremes. For example, consumers that demand organically grown produce may need to accept fruit that is smaller or has some imperfections.

While organic growing has its place, O'Connor also uses hydroponics and controlled environments to grow his plants. Plants that are grown hydroponically are not in a living environment — O'Connor's rest in hay bales, pebbles and water. Instead of drawing nutrients from the soil, the plants are supplied with exactly what they need through a drip-line. Hydroponic gardens are efficient, portable and can be grown anywhere.

In controlled environment chambers, science is king. The amounts of light, nutrients and water that plants receive are controlled down to minute amounts in chambers that resemble large coolers.

“With hydroponics, I use 60 percent less water [than traditional growing] and I can produce food year-round. Controlled environment agriculture lets me produce more product faster,” O'Connor said, noting that he can grow lettuce from a seed to harvest in 36 days using the system. “If I'm a business person, I'd be a fool not to pursue good business decisions that are also look environmental decisions.”

However, O'Connor knows that striking the balance between growing techniques isn't simple.

“It's complex. I'm the last person to ever say this is right or wrong,” he said. “This is where we are, so now the question is where do we go from here to grow food for nine billion people?”

New techniques like genetically modified plants and synthetic biology just add to the complexity.

“We're not going to put the genie back in the bottle,” O'Connor said. “The bottom line is we want to help home or commercial growers get the most out of growing with the least negatives and the smallest environmental impact.”

For O'Connor and Salazar, trying new things is a philosophy that defines their lives.

“Our culture says that you should follow this little path,” O'Connor said. “But you can live successfully by your own path. Take a chance on doing stuff differently. If you never test your limits, you won't grow. People say that we're so lucky, but luck has nothing to do with it. We've sacrificed to do what we do.”

Sitting in his castle, eating fresh raspberries from the garden, O'Connor looks very content with his life. However, he doesn't define himself by the gardens, or even the castle.

“I'm passionate about life in general,” he said. “If the castle burned down tomorrow we would look for something else. I'm a huge believer that live is a blank canvas. You write the final story.”